mybatis/mybatis-plus模糊查询语句特殊字符转义拦截器
在开发中，我们通常会遇到这样的情况。用户在录入信息是录入了‘%'，而在查询时无法精确匹配‘%'。究其原因，‘%'是MySQL的关键字，如果我们想要精确匹配‘%'，那么需要对其进行转义。
1.使用mybatis提供的拦截器拦截所有的查询请求。
具体实现在代码中均有注释
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.StringUtils;
import org.apache.ibatis.executor.Executor;
import org.apache.ibatis.mapping.BoundSql;
import org.apache.ibatis.mapping.MappedStatement;
import org.apache.ibatis.plugin.*;
import org.apache.ibatis.session.ResultHandler;
import org.apache.ibatis.session.RowBounds;
import java.util.*;
@Intercepts({@Signature(type = Executor.class, method = "query", args = {MappedStatement.class, Object.class, RowBounds.class, ResultHandler.class})})
@Slf4j
public class MybatisLikeSqlInterceptor implements Interceptor {
private final static String SQL_LIKE = " like ";
private final static String SQL_PLACEHOLDER = "?";
private final static String SQL_PLACEHOLDER_REGEX = "\\?";
private static Map<Class, AbstractLikeSqlConverter> converterMap = new HashMap<>(4);
static {
converterMap.put(Map.class, new MapLikeSqlConverter());
converterMap.put(Object.class, new ObjectLikeSqlConverter());
}
@Override
public Object intercept(Invocation invocation) throws Throwable {
Object[] args = invocation.getArgs();
MappedStatement statement = (MappedStatement) args[0];
Object parameterObject = args[1];
BoundSql boundSql = statement.getBoundSql(parameterObject);
String sql = boundSql.getSql();
this.transferLikeSql(sql, parameterObject, boundSql);
return invocation.proceed();
}
@Override
public Object plugin(Object target) {
return Plugin.wrap(target, this);
}
@Override
public void setProperties(Properties arg0) {
}
private void transferLikeSql(String sql, Object parameterObject, BoundSql boundSql) {
if (!isEscape(sql)) {
return;
}
sql = sql.replaceAll(" {2}", " ");
// 获取关键字的个数（去重）
Set<String> fields = this.getKeyFields(sql, boundSql);
if (fields == null) {
return;
}
// 此处可以增强,不止是支持Map对象,Map对象仅用于传入的条件为Map或者使用@Param传入的对象被Mybatis转为的Map
AbstractLikeSqlConverter converter;
// 对关键字进行特殊字符“清洗”，如果有特殊字符的，在特殊字符前添加转义字符（\）
if (parameterObject instanceof Map) {
converter = converterMap.get(Map.class);
} else {
converter = converterMap.get(Object.class);
}
converter.convert(sql, fields, parameterObject);
}
private boolean isEscape(String sql) {
return this.hasLike(sql) && this.hasPlaceholder(sql);
}
private boolean hasLike(String str) {
if (StringUtils.isBlank(str)) {
return false;
}
return str.toLowerCase().contains(SQL_LIKE);
}
private boolean hasPlaceholder(String str) {
if (StringUtils.isBlank(str)) {
return false;
}
return str.toLowerCase().contains(SQL_PLACEHOLDER);
}
private Set<String> getKeyFields(String sql, BoundSql boundSql) {
String[] params = sql.split(SQL_PLACEHOLDER_REGEX);
Set<String> fields = new HashSet<>();
for (int i = 0; i < params.length; i++) {
if (this.hasLike(params[i])) {
String field = boundSql.getParameterMappings().get(i).getProperty();
fields.add(field);
}
}
return fields;
}
}2.定义SQL语句转义模板，分别对Map和Object对象进行处理
2.1 定义AbstractLikeSqlConverter
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.StringUtils;
import java.beans.IntrospectionException;
import java.beans.PropertyDescriptor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.Set;
@Slf4j
public abstract class AbstractLikeSqlConverter<T> {
private final static String LIKE_SQL_KEY = "%";
private final static String[] ESCAPE_CHAR = new String[]{LIKE_SQL_KEY, "_", "\\"};
private final static String MYBATIS_PLUS_LIKE_SQL = " like ?";
private final static String MYBATIS_PLUS_WRAPPER_PREFIX = "ew.paramNameValuePairs.";
final static String MYBATIS_PLUS_WRAPPER_KEY = "ew";
final static String MYBATIS_PLUS_WRAPPER_SEPARATOR = ".";
final static String MYBATIS_PLUS_WRAPPER_SEPARATOR_REGEX = "\\.";
final static String REPLACED_LIKE_KEYWORD_MARK = "replaced.keyword";
public void convert(String sql, Set<String> fields, T parameter) {
for (String field : fields) {
if (this.hasMybatisPlusLikeSql(sql)) {
if (this.hasWrapper(field)) {
// 第一种情况：在业务层进行条件构造产生的模糊查询关键字,使用QueryWrapper,LambdaQueryWrapper
this.transferWrapper(field, parameter);
} else {
// 第二种情况：未使用条件构造器，但是在service层进行了查询关键字与模糊查询符`%`手动拼接
this.transferSelf(field, parameter);
}
} else {
// 第三种情况：在Mapper类的注解SQL中进行了模糊查询的拼接
this.transferSplice(field, parameter);
}
}
}
public abstract void transferWrapper(String field, T parameter);
public abstract void transferSelf(String field, T parameter);
public abstract void transferSplice(String field, T parameter);
String escapeChar(String before) {
if (StringUtils.isNotBlank(before)) {
before = before.replaceAll("\\\\", "\\\\\\\\");
before = before.replaceAll("_", "\\\\_");
before = before.replaceAll("%", "\\\\%");
}
return before;
}
boolean hasEscapeChar(Object obj) {
if (!(obj instanceof String)) {
return false;
}
return this.hasEscapeChar((String) obj);
}
void resolveObj(String field, Object parameter) {
if (parameter == null || StringUtils.isBlank(field)) {
return;
}
try {
PropertyDescriptor descriptor = new PropertyDescriptor(field, parameter.getClass());
Method readMethod = descriptor.getReadMethod();
Object param = readMethod.invoke(parameter);
if (this.hasEscapeChar(param)) {
Method setMethod = descriptor.getWriteMethod();
setMethod.invoke(parameter, this.escapeChar(param.toString()));
} else if (this.cascade(field)) {
int index = field.indexOf(MYBATIS_PLUS_WRAPPER_SEPARATOR) + 1;
this.resolveObj(field.substring(index), param);
}
} catch (IntrospectionException | IllegalAccessException | InvocationTargetException e) {
log.error("反射 {} 的 {} get/set方法出现异常", parameter, field, e);
}
}
boolean cascade(String field) {
if (StringUtils.isBlank(field)) {
return false;
}
return field.contains(MYBATIS_PLUS_WRAPPER_SEPARATOR) && !this.hasWrapper(field);
}
private boolean hasMybatisPlusLikeSql(String sql) {
if (StringUtils.isBlank(sql)) {
return false;
}
return sql.toLowerCase().contains(MYBATIS_PLUS_LIKE_SQL);
}
private boolean hasWrapper(String field) {
if (StringUtils.isBlank(field)) {
return false;
}
return field.contains(MYBATIS_PLUS_WRAPPER_PREFIX);
}
private boolean hasEscapeChar(String str) {
if (StringUtils.isBlank(str)) {
return false;
}
for (String s : ESCAPE_CHAR) {
if (str.contains(s)) {
return true;
}
}
return false;
}
}2.2 定义MapLikeSqlConverter处理Map类型参数的情况
import com.baomidou.mybatisplus.core.conditions.AbstractWrapper;
import java.util.Map;
import java.util.Objects;
public class MapLikeSqlConverter extends AbstractLikeSqlConverter<Map> {
@Override
public void transferWrapper(String field, Map parameter) {
AbstractWrapper wrapper = (AbstractWrapper) parameter.get(MYBATIS_PLUS_WRAPPER_KEY);
parameter = wrapper.getParamNameValuePairs();
String[] keys = field.split(MYBATIS_PLUS_WRAPPER_SEPARATOR_REGEX);
// ew.paramNameValuePairs.param1，截取字符串之后，获取第三个，即为参数名
String paramName = keys[2];
String mapKey = String.format("%s.%s", REPLACED_LIKE_KEYWORD_MARK, paramName);
if (parameter.containsKey(mapKey) && Objects.equals(parameter.get(mapKey), true)) {
return;
}
if (this.cascade(field)) {
this.resolveCascadeObj(field, parameter);
} else {
Object param = parameter.get(paramName);
if (this.hasEscapeChar(param)) {
String paramStr = param.toString();
parameter.put(keys[2], String.format("%%%s%%", this.escapeChar(paramStr.substring(1, paramStr.length() - 1))));
}
}
parameter.put(mapKey, true);
}
@Override
public void transferSelf(String field, Map parameter) {
if (this.cascade(field)) {
this.resolveCascadeObj(field, parameter);
return;
}
Object param = parameter.get(field);
if (this.hasEscapeChar(param)) {
String paramStr = param.toString();
parameter.put(field, String.format("%%%s%%", this.escapeChar(paramStr.substring(1, paramStr.length() - 1))));
}
}
@Override
public void transferSplice(String field, Map parameter) {
if (this.cascade(field)) {
this.resolveCascadeObj(field, parameter);
return;
}
Object param = parameter.get(field);
if (this.hasEscapeChar(param)) {
parameter.put(field, this.escapeChar(param.toString()));
}
}
private void resolveCascadeObj(String field, Map parameter) {
int index = field.indexOf(MYBATIS_PLUS_WRAPPER_SEPARATOR);
Object param = parameter.get(field.substring(0, index));
if (param == null) {
return;
}
this.resolveObj(field.substring(index + 1), param);
}
}2.3 定义ObjectLikeSqlConverter处理Object类型参数的情况
import lombok.extern.slf4j.Slf4j;
@Slf4j
public class ObjectLikeSqlConverter extends AbstractLikeSqlConverter<Object> {
@Override
public void transferWrapper(String field, Object parameter) {
// 尚未发现这种情况
}
@Override
public void transferSelf(String field, Object parameter) {
// 尚未发现这种情况
}
@Override
public void transferSplice(String field, Object parameter) {
this.resolveObj(field, parameter);
}
}3. 注册到Spring中
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
@Configuration
public class MybatisLikeSqlConfig {
@Bean
public MybatisLikeSqlInterceptor mybatisSqlInterceptor() {
return new MybatisLikeSqlInterceptor();
}
}到此，即可进行关键字的精确匹配。
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